Microdermabrasion

Researchers have reported that microdermabrasion can improve the appearance of sun damaged skin by inducing molecular changes.  A study of 40 people aged 50 to 83 demonstrated that aggressive non-ablative microdermabrasion is an effective procedure to stimulate collagen.  They only adverse side effect reported was mild temporary erythema (redness).
The authors concluded that microdermabrasion can elicit significant skin rejuvenation. 

Archives of Dermatology 2009; 145: 114-122